1. Field of the Invention
This invention relates in general to circuits for determining the phase modulation disturbances in a signal which is passed through a test object.
2. Description of the Prior Art
Phase-jitter has previously been measured at measuring points which lie in the range of the carrier frequency operated portions or stages of a carrier-frequency transmission system and the signal being measured is picked up and converted with a carrier frequency heterodyne receiver of a level measuring apparatus and is converted into the original frequency position and fed in at the low frequency input and then is evaluated by means of a "phase-jitter" measuring apparatus operating in the low frequency range. Such prior art systems require in addition to the conventional apparatus expensive apparatus and numerous operating stages and settings of the interconnected devices which makes the measurement time consuming, complicated and expensive.